Fix broken SF3 support for Android binaries (#890)

Libsndfile was unintentionally compiled without OGG/Vorbis support. That's because libopus was missing. When compiling libsndfile with autotools [you get a nice warning](9349a566e2/configure.ac (L381-L386)). When using CMake you don't...

Solution: Compile libopus before compiling libsndfile. Now it reports

```
-- The following features have been enabled:

 * ENABLE_EXTERNAL_LIBS, enable FLAC, Vorbis, and Opus codecs
```

.azure/azure-pipelines-android.yml

@@ -43,6 +43,7 @@ variables:
   INSTPATCH_VERSION: '1.1.6'
   VORBIS_VERSION: '1.3.7'
   OGG_VERSION: '1.3.4'
+  OPUS_VERSION: '1.3.1'
   # flac 1.3.3 is completely broken: pkgconfig is incorrectly installed, compilation failure, etc.; use recent master instead
   FLAC_VERSION: '27c615706cedd252a206dd77e3910dfa395dcc49'
 
@@ -158,12 +159,15 @@ jobs:
         wget -O flac-${FLAC_VERSION}.tar.gz https://github.com/xiph/flac/archive/${FLAC_VERSION}.tar.gz
         tar xf flac-${FLAC_VERSION}.tar.gz
 
+        wget -O opus-${OPUS_VERSION}.tar.gz https://github.com/xiph/opus/archive/refs/tags/v${OPUS_VERSION}.tar.gz
+        tar xf opus-${OPUS_VERSION}.tar.gz
+
       displayName: 'Download Dependencies'
       workingDirectory: $(DEV)
 
     - task: Cache@2
       inputs:
-        key: '$(ARCH) | $(DEV)/*.tar.gz | cacheVersion1'
+        key: '$(ARCH) | $(DEV)/*.tar.gz | cacheVersion2'
         path: '$(PREFIX)'
         cacheHitVar: 'CACHE_RESTORED'
       displayName: 'Cache fluidsynth dependency libraries'
@@ -495,6 +499,21 @@ jobs:
       condition: always()
       workingDirectory: $(DEV)
 
+    # another broken xiph project that doesn't specify the C standard and keeps complaining of you don't have C99
+    - template: cmake-android.yml
+      parameters:
+        sourceDir: 'opus-$(OPUS_VERSION)'
+        cmakeArgs: '-DBUILD_PROGRAMS=0 -DOPUS_MAY_HAVE_NEON=1 -DCMAKE_C_STANDARD=99 -DCMAKE_C_STANDARD_REQUIRED=1'
+
+    - script: |
+        ls -la opus-${OPUS_VERSION}/build/CMakeFiles/
+        cat opus-${OPUS_VERSION}/build/CMakeFiles/CMakeError.log
+        cat opus-${OPUS_VERSION}/build/CMakeFiles/CMakeOutput.log
+        true
+      displayName: 'Print OPUS Cmake Error Log'
+      condition: always()
+      workingDirectory: $(DEV)
+
     - template: cmake-android.yml
       parameters:
         sourceDir: 'libsndfile-$(SNDFILE_VERSION)'
@@ -606,6 +625,7 @@ jobs:
         ls libintl.so
         ls liboboe.so
         ls libogg.so
+        ls libopus.so
         ls libsndfile.so
         ls libvorbis.so
         ls libvorbisenc.so

.azure/cmake-android.yml

@@ -33,6 +33,7 @@ steps:
     cmake -G "Unix Makefiles" \
         -DCMAKE_MAKE_PROGRAM=make \
         -DCMAKE_TOOLCHAIN_FILE=${NDK}/build/cmake/android.toolchain.cmake \
+        -DCMAKE_BUILD_TYPE=RelWithDebInfo \
         -DANDROID_NATIVE_API_LEVEL=${ANDROID_API} \
         -DANDROID_ABI=${ANDROID_ABI_CMAKE} \
         -DANDROID_TOOLCHAIN=${CC} \